Who will be the next UK PM? Rishi Sunak, Boris Johnson and other top contenders

Liz Truss resigned as the UK prime minister on Thursday after chaotic six weeks of her government, becoming the shortest-serving premier in the country's history.

The Conservative Party is now expected to appoint a new leader by October 28. Here are the frontrunners for the position:

1) Rishi Sunak

Rishi Sunak was Liz Truss' chief competitor in the PM race after Boris Johnson's exit in July. He lost the race by 21,000 as votes as he failed to convince his colleagues of the risk of Truss' tax plans, the BBC reported.

But now, some are placing their bets on Sunak, after him being proven right by Truss' chaotic tenure, according to news agency AFP.

Rishi Sunak is back in the limelight after losing out the PM race to Liz Truss.

2) Boris Johnson

Boris Johnson exited in July after a series of controversies, but he still has support within his party and the British parliament, the BBC reported. Ever since his resignation, there had been speculation that he will try to make a comeback.

The former beleaguered British prime minister still has allies.

3) Penny Mordaunt 

Penny Mordaunt, an early favourite to replace Boris Johnson, returned to the spotlight this week when she faced questions in parliament about the economic chaos in the UK, AFP reported. She was considered to have managed the situation well.

But Maordaunt has also been criticised, with some deeming her inept her previous roles.

Penny Mordaunt, leader of the House of Commons.

4) Ben Wallace

The UK defence secretary has gained repute as his country is seen playing a key role in the global response to Russian aggression in Ukraine, AFP reported.

Defence secretary Ben Wallace has emerged as the most popular member of the UK government amid the Ukraine war.

While initially hesitant to run for the PM post he recently said: "I don't rule it out."

(With inputs from AFP)